.list{
    width: 300px;
    border: 1px solid black;
    margin: 0 auto;
    list-style: none;
    padding: 0;
    text-align: center;
    li{
        height: 30px;
        line-height: 30px;
        border: 1px solid pink;
        &:nth-child(2n-1){
            background: yellow;
        }
        &:nth-child(2n){
            background: purple;
        }
        &:hover{
            background:blue;
            color: #FFF;
        }
    }

}